EVALUATION OF FLUORINE-18-BPA-FRUCTOSE FOR BORON NEUTRON-CAPTURE TREATMENT PLANNING

Boron neutron capture therapy (BNCT) using 4-[B-10]boronophenylalanine -fructose (BPA-Fr) is in Phase II clinical trials to validate BNCT as a treatment for glioblastoma multiforme and melanoma. Successful BNCT depends on knowledge of the distribution of boron-containing agents in both tumor and normal tissue as currently determined by chemical conf irmation of boron deposition in surgically removed malignant tissue be fore BNCT. Methods: We used PET to noninvasively obtain in vivo inform ation on the pharmacokinetics of the F-18-labeled analog of BPA-Fr in two patients with glioblastoma multiforme. Time-activity curves genera ted from the bolus injection of F-18-BPA-Fr were convolved to simulate a continuous infusion used for BNCT therapy. Results: Distribution of F-18-BPA-Fr by PET was found to be consistent with tumor as identifie d by MR imaging. The F-18-BPA-Fr tumor-to-normal brain uptake ratio wa s 1.9 in Patient 1 and 3.1 in Patient 2 at 52 min after injection. The F-18-BPA-Fr uptake ratio in glioblastoma paralleled that of nonlabele d BPA-Fr seen in patients as previously determined by boron analysis o f human glioblastoma tissue obtained from pre-BNCT surgical biopsy. Co nclusion: Knowledge of the biodistribution of BPA-Fr enables pre-BNCT calculation of expected tissue dosimetry for a selected dose of BPA-Fr at a specific neutron exposure. Fluorine-18-BPA-Fr PET is capable of providing in vivo BPA-Fr biodistribution data that may prove valuable for patient selection and pre-BNCT treatment planning.